With miniature omnis, boundary mounted to a vertical wall, I simply gaff tape them in place directly to the surface, no stand or mounts required. I do have some hard rubber boundary mounts made for the minature DPA omnis which work nicely and protect them from being crushed if accidentally stepped on when used on the floor. The rubber mounts can similary be taped to a wall or even a person.

Rocks, your construction looks similar to this recommended Shopes accessory: http://www.schoeps.de/en/schoeps-recommends/turtle, which both suspends the microphone using elastic bands to eliminate solid-born handling noise (vibration transmitted through the floor) and offers protection from being trampled upon, although it looks like the capsule portion protrudes from the protective housing and is vulnerable. That can be used for directional microphones as well as omnis, and that blue superCMIT shotgun sticking out right at foot level looks very vulnerable to me!

You want to get the capsule as close as possible to the surface for best results. I've used non-minature omnis placed directly on neoprene rubber 'mouse-pads' laying on the floor with a sandbag (actually they were lead-shot bags) on top, which damped vibrations and also protected the microphones. Obviously the capsule has to protrude enough not to be obscured by the sandbag, and the polar pattern to the rear is somewhat modified by the sandbag.

Volt, for boundary mounted recording of the marching band out on the field, you'd want a vertical boundary like a wall that faces the field. You might be able to setup two stands right up against a large wall facing the field, and arrange the mic stands so the microphone capsules are only a 1/4" or so from the wall surface, facing upwards or to either side. With foam windscreens on the mics you could push them right up against the wall. If both omnis are mounted on the same wall, then you'll want to space them as you would A-B omnis in free space. If you had a triangular wall corner that points towards the center of the field (doubtful, but who knows), or are using two pieces of perspex (plexiglass) or plywood or a couple folding tables or whatever as boundary surfaces which you can arrange however you like (anything hard, flat and large enough will work, the larger the better, 4' square or even more is best) you could arrange the microphones closer together with the two surfaces angled away from each other like directional microphones. That will introduce more level difference and less time of arrival differences between channels.

If you'd rather not hear them marching left and right in the resulting image, back and forth to opposite ends of the field, spacing them A-B more widely on one surface will get that open spaced omni bigness and ambience (appropriate for this I think) without such hard panned imaging effects.

I do think boundary mounted omnis may be a good choice for a marching band on a field if you are recording from the pressbox. The technique seems to be very good at providing good clarity while minimizing ambient reverberance when recording from a far distance.

Thanks for these great ideas. I actually tried to use my X-Qs once in a similar way to the floor setup you described as stage mics for a musical theater production. They covered the stage great, but even with damping material on top and an acoustic barrier (music stand covered with foam) behind them, they picked up too much of the drum set and bass from the pit orchestra to use them during a show. Instead I borrowed a set of AT PCC mics which were just the ticket. At my wife's school they have a set of Crown PCCs which are VERY nice for this application.

Unfortunately, I won't have permission, time, or space to do a boundary setup, and I won't even have the ability to bring my tall stand in to the stadium, let alone large plexiglass panels. There isn't a wall to tape onto - the stands are made of aluminum on an open frame, which is quite resonant. It's kind of a 30-second setup and breakdown deal, even at home games where I more or less have the run of the place. The top of the press box is the only spot where I really do have the freedom to separate mics at any significant distance, and as I said I also need to think of good locations for fixed-angle video.

The good news though is that my Line Audio CM3s just came in the mail today, and I think they're going to work out well for when I have to be very compact. I realize omnis may be preferable for a variety of reasons, but these are closer to a subcardiod pattern and don't perform quite like normal cardiods. I did a quick wind test with them and found them to be no more sensitive to wind noise than my omnis (with the rats of course).

This Thursday is my first time I'm recording the band, as the "before season" first run-through for parents. From what I understand I'll be on top of a tall scaffolding on the running track just off the football field. So I'm going to climb up there and clamp my CM3s in a NOS arrangement in front of me, while I am also taking care of video. I won't have access to the scaffolding after this one time, but that's where I'm asked to be this week. From there on out, I'll be top of the press box or in the stands. If it comes out well, I'll post a short sample if possible.

At this point, I think I should re-title the thread as we've really gone wholly over to marching band recording!

Good Lord - I've seen that IsoMike setup used for orchestral recordings before, but there's got to be over a hundred grand worth of equipment there (a large chunk of which may be Ray Kimber's expensive cables). It wish it said which mikes were being used - I think the orchestral one I saw had Neumann TLM49s or something. Great sound though, and I highly approve of the Shostakovich 10th excerpt in a Drum Corps show. Way beyond the level of high school marching band I'm working with but really cool.

If we're talking DCI, my favorite corps has always been Carolina Crown. They were FINALLY rewarded with a championship last year, earning a perfect brass score. No other corps plays with this level of cohesion or musical expression.I believe this is the official produced video, and I see 3 main mics at the 35, 50, and 35, with spots on the pit instruments and powered PA. If you pause at around 1:10 it looks like the center may be a DIN array but I can't be sure.https://www.youtube.com/watch?v=sKdB40k98jM

Please correct my limited understanding of boundary mics. I got the impression that a boundary mic is essentially an omni mic placed on a flat surface (the boundary), but the mic usually goes in a housing to protect it from being stepped on as many boundary mics are floor mounted?

A while ago, I had drilled out some aluminum channel as a housing to try this out with some Rode NT45 omnis, but that's as far as I got with this. Seems like I had thought about suspending the mics with rubber bands inside the housing and then mounting the channel to a flat surface.

Please correct my limited understanding of boundary mics. I got the impression that a boundary mic is essentially an omni mic placed on a flat surface (the boundary), but the mic usually goes in a housing to protect it from being stepped on as many boundary mics are floor mounted?

A while ago, I had drilled out some aluminum channel as a housing to try this out with some Rode NT45 omnis, but that's as far as I got with this. Seems like I had thought about suspending the mics with rubber bands inside the housing and then mounting the channel to a flat surface.

"I do have some hard rubber boundary mounts made for the minature DPA omnis which work nicely and protect them from being crushed if accidentally stepped on when used on the floor. The rubber mounts can similary be taped to a wall or even a person."

Haven't seen these or even heard of them before. Do you have a picture or a link to them, Gutbucket?

They work with any of the 406x series miniature omnis. I've also posted close up photos of the slot and inserting the microphone somwhere here on the site years ago. They also come in white. I've been meaning to pickup some white ones for mounting on a white undershirt, for some applications they work better than the DPA concealers designed to reduce fabric noise when the microphones are mounted under clothing.

Good Lord - I've seen that IsoMike setup used for orchestral recordings before, but there's got to be over a hundred grand worth of equipment there (a large chunk of which may be Ray Kimber's expensive cables). It wish it said which mikes were being used - I think the orchestral one I saw had Neumann TLM49s or something. Great sound though, and I highly approve of the Shostakovich 10th excerpt in a Drum Corps show. Way beyond the level of high school marching band I'm working with but really cool.

If we're talking DCI, my favorite corps has always been Carolina Crown. They were FINALLY rewarded with a championship last year, earning a perfect brass score. No other corps plays with this level of cohesion or musical expression.I believe this is the official produced video, and I see 3 main mics at the 35, 50, and 35, with spots on the pit instruments and powered PA. If you pause at around 1:10 it looks like the center may be a DIN array but I can't be sure.https://www.youtube.com/watch?v=sKdB40k98jM

I highly approve of a Phillip Glass excerpt!

Honestly I think the IsoMike is a bit ridiculous, but in an interesting way at least. I met RK and bought a few of his IsoMike recordings at a headphone conference back in '09 I think, just after I had heard about his giant baffle. He was sitting by himself looking a bit bored, maning a Kimber table that had a playback setup with phones and a Korg DSD recrorder. I was suprised to find him there and having built and used a few odd-shaped and sized (far smaller!) Jecklin-like baffles myself I hoped to talk a bit about audio engineering and recording with him to see what I could learn. He just wanted to talk cables and sell recordings and was very disinterested and seemed sort of intimidated when I asked a few technical questions about the IsoMike. I was rather disappointed and moved on. shurg.

Yeah the closer the better for an even response across all frequencies down to the lower limit imposed by the area of the boundary itself.

The closer the diaphragm is to the boundary, the higher in frequency the effect manifests as boundary reinforcement rather than comb filtering coloration. But in practical terms I'm not sure how much that really matters. Tapers record all the time with microphones on low stands 6" to a couple feet above the surface of the stage around here without major issues lower in frequency. Even a normal height mic-stand is within the boundary reinforcement zone at the lowest frequencies. Most everyone here will be familiar with the subjective difference in level of the subwoofers compared to the rest of the spectrum at highly amplified venues when standing up verses sitting down, the low end can get deafening closer to the floor, especially when going from standing to sitting directly on the ground outside at a festival. That’s lower frequency boundary effect.

When I started placing mics just a few inches above the stage for recording acoustic jazz to minimize my visual impact, I was initially concerned about combing from reflections bouncing off the highly reflective wooden floor but never had any audible issues. [edit- sometimes that inculded LD microphones oriented sideways in their shock mounts, mostly to get the desired spacing I wanted, but that orientaion also placed them lower, with the diaphrams about 2-1/2 inches above the floor surface.]

Right, I mentioned LF partly because the boundary effect for that region extends so much farther from the surface and wanted to relate that to the personal listening experience of others reading this. And sure, the HF combing will be especially audible with white noise. I just haven't found it to be a big problem with mics on a stage, or mics relatively close to a wall boundary when recording music in my own experience. I thought I would find it to be more significant but thankfully haven't found that to be the case.

Overheads on drums with mics between the cymbals and a low ceiling I can see as being more problematic, especially in a studio environment. The ceiling fan over my couch at home really screws with the sound of an acoustic guitar with weird HF phasing, just by ear. The blades are moving and shifting the combing around so it's especially audible and annoying. But it's summertime and hot so I just put up with it when thumbing around for my own non-recorded entertainment.

More on the guitar and ceiling fan thing- when I first I took notice of that and realized what was going on, my next thought was that it was an excellent example of making something consciously noticeable which normally isn't, even if it is always quite easily measurable and most definitely effecting timbre. The effects of the room boundaries and reflections off nearby surfaces like the ceiling and fan blades unquestionably affect the sound of the guitar in the room. But it normally only becomes obvious when moving to different rooms or listening to recordings made in different rooms. Likewise the effects on timbre are of the same magnitude but aren’t consciously perceptible with the fan off, although they are very obvious and objectionable with the blades moving causing audible comb-shifting. A static comb-filter may not be a problem even though it may be strong and easily measureable. It could be but it isn’t always, and I haven’t found it very problematic when I’ve placed mics near static boundaries recording live music performaces.

I wouldn't want people actually walking on them!, but it will probably fully support a heavy person's accidental foot-step without damage unless they're wearing cleats. The cable is exposed and more prone to damage. The rubber is pretty dense and non-compressible. I've used them on stage and I don't think I've actually had anyone step directly on them, and was able to route the thin gage cable along the groove between loose fitting floor boards secured with a strip of gaff tape over it.